Prepare a 6-inch cast iron skillet (if you don't have cast iron, use a 6-inch round oven safe dutch oven or bowl). Using ½ teaspoon olive oil and a paper towel, lightly coat the entire inside of dish to help prevent sticking. This will also help the bread to develop a nice, crispy crust. Alternatively, instead of olive oil, you can line the pan with parchment paper, no need to coat with any oil or spray.
If you don't have a warm spot to place the dough to proof, set your oven to the 'Proof' setting, which is about 100° F.
In a small bowl, combine warm water (about 110° F), sugar and yeast. Gently stir and set aside for 5-10 minutes. The yeast should start to bubble and foam at the top, which indicates your yeast is good!
In a stand mixer, combine gluten free flour, guar gum, salt, black pepper, Italian seasoning, and chopped rosemary until mixed (about 30 seconds).
Once the yeast has become bubbly and foamy, pour into the flour mixture. Add 2 Tbs olive oil. Mix on medium speed for 2-3 minutes, scraping down the sides if needed. The dough will be sticky.
Transfer the dough to your prepared cast iron skillet. Using a spatula (get it wet to help prevent sticking), gently mound the dough into a ball, smoothing out the dough as you go. The ball should be about 4 inches in diameter.
Using the remaining 1 teaspoon olive oil, gently rub it over the dough (this prevents the dough from drying out as it will not be covered during proofing. It also helps the bread develop a crispy crust.) Place the pan in a warm spot (I like the proof setting on my oven!) and allow the dough to double in size. This can take anywhere from 35-45 minutes, depending on the temperature. Keep an eye on the dough starting around 35 minutes to make sure it hasn't developed beyond your pan.
Toward the end of the dough proof, preheat your oven to 425° F (removing the pan from the oven if necessary).
Sprinkle remaining ¼ teaspoon kosher salt on the dough. If desired, make two slashes with a sharp knife on the top (purely decorative), but be careful not to slash too deep. Place in oven and bake for 30-35 minutes, or until the outside crust is lightly browned.
Remove from oven and allow to cool slightly before tearing into.
Eat warm as is, or, our family favorite is to dip the bread into a small plate of olive oil and balsamic vinegar. This bread is best eaten the day of!